Acadesine is the prototype of a new class of therapeutic compounds termed adenosine regulating agents. Acadesine is pharmacologically silent in normal circumstances, but its activity becomes operative during situations of net ATP catabolism, when it increases local adenosine levels. Thus acadesine is able to harness the beneficial effects of this protective autacoid without the limiting side effects associated with using adenosine itself or an adenosine mimetic or transport inhibitor. The demonstrated efficacy of acadesine in various models of myocardial ischaemia and the preliminary clinical results 48 indicate that acadesine and other ARAs could represent important new additions to the cardiologist's armamentarium to combat myocardial ischaemia and its sequelae.